Package: release.debian.org Severity: normal Tags: stretch User: release.debian....@packages.debian.org Usertags: pu
This includes patch for CVE-2019-5736. As discussed with security-team, there's no urgency to go through scurity-upload. So let's fix it through stable-proposed-updates. -- Shengjing Zhu
diff -Nru runc-0.1.1+dfsg1/debian/changelog runc-0.1.1+dfsg1/debian/changelog --- runc-0.1.1+dfsg1/debian/changelog 2017-02-01 23:17:54.000000000 +0800 +++ runc-0.1.1+dfsg1/debian/changelog 2019-03-19 00:50:07.000000000 +0800 @@ -1,3 +1,10 @@ +runc (0.1.1+dfsg1-2+deb9u1) stretch; urgency=medium + + * Team upload. + * Add patch to address CVE-2019-5736 (Closes: #922050) + + -- Shengjing Zhu <z...@debian.org> Tue, 19 Mar 2019 00:50:07 +0800 + runc (0.1.1+dfsg1-2) unstable; urgency=medium * Team upload. diff -Nru runc-0.1.1+dfsg1/debian/patches/CVE-2019-5736.patch runc-0.1.1+dfsg1/debian/patches/CVE-2019-5736.patch --- runc-0.1.1+dfsg1/debian/patches/CVE-2019-5736.patch 1970-01-01 08:00:00.000000000 +0800 +++ runc-0.1.1+dfsg1/debian/patches/CVE-2019-5736.patch 2019-03-19 00:50:07.000000000 +0800 @@ -0,0 +1,572 @@ +From: Shengjing Zhu <z...@debian.org> +Date: Sun, 10 Mar 2019 17:47:46 +0800 +Subject: CVE-2019-5736 + +Backport upstream patches for CVE-2019-5736 + +Fix in nsexec.c is adjusted to current version + +Include commits: +2d4a37b427167907ef2402586a8e8e2931a22490 nsenter: cloned_binary: userspace copy fallback if sendfile fails +16612d74de5f84977e50a9c8ead7f0e9e13b8628 nsenter: cloned_binary: try to ro-bind /proc/self/exe before copying +af9da0a45082783f6005b252488943b5ee2e2138 nsenter: cloned_binary: use the runc statedir for O_TMPFILE +2429d59352b81f6b9cc79b5ed26780c5fe6ba4ec nsenter: cloned_binary: expand and add pre-3.11 fallbacks +5b775bf297c47a6bc50e36da89d1ec74a6fa01dc nsenter: cloned_binary: detect and handle short copies +bb7d8b1f41f7bf0399204d54009d6da57c3cc775 nsexec (CVE-2019-5736): avoid parsing environ +0a8e4117e7f715d5fbeef398405813ce8e88558b nsenter: clone /proc/self/exe to avoid exposing host binary to container + +Bug-Debian: https://bugs.debian.org/922050 +--- + libcontainer/nsenter/cloned_binary.c | 516 +++++++++++++++++++++++++++++++++++ + libcontainer/nsenter/nsexec.c | 8 + + 2 files changed, 524 insertions(+) + create mode 100644 libcontainer/nsenter/cloned_binary.c + +diff --git a/libcontainer/nsenter/cloned_binary.c b/libcontainer/nsenter/cloned_binary.c +new file mode 100644 +index 0000000..b410e29 +--- /dev/null ++++ b/libcontainer/nsenter/cloned_binary.c +@@ -0,0 +1,516 @@ ++/* ++ * Copyright (C) 2019 Aleksa Sarai <cyp...@cyphar.com> ++ * Copyright (C) 2019 SUSE LLC ++ * ++ * Licensed under the Apache License, Version 2.0 (the "License"); ++ * you may not use this file except in compliance with the License. ++ * You may obtain a copy of the License at ++ * ++ * http://www.apache.org/licenses/LICENSE-2.0 ++ * ++ * Unless required by applicable law or agreed to in writing, software ++ * distributed under the License is distributed on an "AS IS" BASIS, ++ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. ++ * See the License for the specific language governing permissions and ++ * limitations under the License. ++ */ ++ ++#define _GNU_SOURCE ++#include <unistd.h> ++#include <stdio.h> ++#include <stdlib.h> ++#include <stdbool.h> ++#include <string.h> ++#include <limits.h> ++#include <fcntl.h> ++#include <errno.h> ++ ++#include <sys/types.h> ++#include <sys/stat.h> ++#include <sys/statfs.h> ++#include <sys/vfs.h> ++#include <sys/mman.h> ++#include <sys/mount.h> ++#include <sys/sendfile.h> ++#include <sys/syscall.h> ++ ++/* Use our own wrapper for memfd_create. */ ++#if !defined(SYS_memfd_create) && defined(__NR_memfd_create) ++# define SYS_memfd_create __NR_memfd_create ++#endif ++/* memfd_create(2) flags -- copied from <linux/memfd.h>. */ ++#ifndef MFD_CLOEXEC ++# define MFD_CLOEXEC 0x0001U ++# define MFD_ALLOW_SEALING 0x0002U ++#endif ++int memfd_create(const char *name, unsigned int flags) ++{ ++#ifdef SYS_memfd_create ++ return syscall(SYS_memfd_create, name, flags); ++#else ++ errno = ENOSYS; ++ return -1; ++#endif ++} ++ ++ ++/* This comes directly from <linux/fcntl.h>. */ ++#ifndef F_LINUX_SPECIFIC_BASE ++# define F_LINUX_SPECIFIC_BASE 1024 ++#endif ++#ifndef F_ADD_SEALS ++# define F_ADD_SEALS (F_LINUX_SPECIFIC_BASE + 9) ++# define F_GET_SEALS (F_LINUX_SPECIFIC_BASE + 10) ++#endif ++#ifndef F_SEAL_SEAL ++# define F_SEAL_SEAL 0x0001 /* prevent further seals from being set */ ++# define F_SEAL_SHRINK 0x0002 /* prevent file from shrinking */ ++# define F_SEAL_GROW 0x0004 /* prevent file from growing */ ++# define F_SEAL_WRITE 0x0008 /* prevent writes */ ++#endif ++ ++#define CLONED_BINARY_ENV "_LIBCONTAINER_CLONED_BINARY" ++#define RUNC_MEMFD_COMMENT "runc_cloned:/proc/self/exe" ++#define RUNC_MEMFD_SEALS \ ++ (F_SEAL_SEAL | F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_WRITE) ++ ++static void *must_realloc(void *ptr, size_t size) ++{ ++ void *old = ptr; ++ do { ++ ptr = realloc(old, size); ++ } while(!ptr); ++ return ptr; ++} ++ ++/* ++ * Verify whether we are currently in a self-cloned program (namely, is ++ * /proc/self/exe a memfd). F_GET_SEALS will only succeed for memfds (or rather ++ * for shmem files), and we want to be sure it's actually sealed. ++ */ ++static int is_self_cloned(void) ++{ ++ int fd, ret, is_cloned = 0; ++ struct stat statbuf = {}; ++ struct statfs fsbuf = {}; ++ ++ fd = open("/proc/self/exe", O_RDONLY|O_CLOEXEC); ++ if (fd < 0) ++ return -ENOTRECOVERABLE; ++ ++ /* ++ * Is the binary a fully-sealed memfd? We don't need CLONED_BINARY_ENV for ++ * this, because you cannot write to a sealed memfd no matter what (so ++ * sharing it isn't a bad thing -- and an admin could bind-mount a sealed ++ * memfd to /usr/bin/runc to allow re-use). ++ */ ++ ret = fcntl(fd, F_GET_SEALS); ++ if (ret >= 0) { ++ is_cloned = (ret == RUNC_MEMFD_SEALS); ++ goto out; ++ } ++ ++ /* ++ * All other forms require CLONED_BINARY_ENV, since they are potentially ++ * writeable (or we can't tell if they're fully safe) and thus we must ++ * check the environment as an extra layer of defence. ++ */ ++ if (!getenv(CLONED_BINARY_ENV)) { ++ is_cloned = false; ++ goto out; ++ } ++ ++ /* ++ * Is the binary on a read-only filesystem? We can't detect bind-mounts in ++ * particular (in-kernel they are identical to regular mounts) but we can ++ * at least be sure that it's read-only. In addition, to make sure that ++ * it's *our* bind-mount we check CLONED_BINARY_ENV. ++ */ ++ if (fstatfs(fd, &fsbuf) >= 0) ++ is_cloned |= (fsbuf.f_flags & MS_RDONLY); ++ ++ /* ++ * Okay, we're a tmpfile -- or we're currently running on RHEL <=7.6 ++ * which appears to have a borked backport of F_GET_SEALS. Either way, ++ * having a file which has no hardlinks indicates that we aren't using ++ * a host-side "runc" binary and this is something that a container ++ * cannot fake (because unlinking requires being able to resolve the ++ * path that you want to unlink). ++ */ ++ if (fstat(fd, &statbuf) >= 0) ++ is_cloned |= (statbuf.st_nlink == 0); ++ ++out: ++ close(fd); ++ return is_cloned; ++} ++ ++/* Read a given file into a new buffer, and providing the length. */ ++static char *read_file(char *path, size_t *length) ++{ ++ int fd; ++ char buf[4096], *copy = NULL; ++ ++ if (!length) ++ return NULL; ++ ++ fd = open(path, O_RDONLY | O_CLOEXEC); ++ if (fd < 0) ++ return NULL; ++ ++ *length = 0; ++ for (;;) { ++ ssize_t n; ++ ++ n = read(fd, buf, sizeof(buf)); ++ if (n < 0) ++ goto error; ++ if (!n) ++ break; ++ ++ copy = must_realloc(copy, (*length + n) * sizeof(*copy)); ++ memcpy(copy + *length, buf, n); ++ *length += n; ++ } ++ close(fd); ++ return copy; ++ ++error: ++ close(fd); ++ free(copy); ++ return NULL; ++} ++ ++/* ++ * A poor-man's version of "xargs -0". Basically parses a given block of ++ * NUL-delimited data, within the given length and adds a pointer to each entry ++ * to the array of pointers. ++ */ ++static int parse_xargs(char *data, int data_length, char ***output) ++{ ++ int num = 0; ++ char *cur = data; ++ ++ if (!data || *output != NULL) ++ return -1; ++ ++ while (cur < data + data_length) { ++ num++; ++ *output = must_realloc(*output, (num + 1) * sizeof(**output)); ++ (*output)[num - 1] = cur; ++ cur += strlen(cur) + 1; ++ } ++ (*output)[num] = NULL; ++ return num; ++} ++ ++/* ++ * "Parse" out argv from /proc/self/cmdline. ++ * This is necessary because we are running in a context where we don't have a ++ * main() that we can just get the arguments from. ++ */ ++static int fetchve(char ***argv) ++{ ++ char *cmdline = NULL; ++ size_t cmdline_size; ++ ++ cmdline = read_file("/proc/self/cmdline", &cmdline_size); ++ if (!cmdline) ++ goto error; ++ ++ if (parse_xargs(cmdline, cmdline_size, argv) <= 0) ++ goto error; ++ ++ return 0; ++ ++error: ++ free(cmdline); ++ return -EINVAL; ++} ++ ++enum { ++ EFD_NONE = 0, ++ EFD_MEMFD, ++ EFD_FILE, ++}; ++ ++/* ++ * This comes from <linux/fcntl.h>. We can't hard-code __O_TMPFILE because it ++ * changes depending on the architecture. If we don't have O_TMPFILE we always ++ * have the mkostemp(3) fallback. ++ */ ++#ifndef O_TMPFILE ++# if defined(__O_TMPFILE) && defined(O_DIRECTORY) ++# define O_TMPFILE (__O_TMPFILE | O_DIRECTORY) ++# endif ++#endif ++ ++static int make_execfd(int *fdtype) ++{ ++ int fd = -1; ++ char template[PATH_MAX] = {0}; ++ char *prefix = secure_getenv("_LIBCONTAINER_STATEDIR"); ++ ++ if (!prefix || *prefix != '/') ++ prefix = "/tmp"; ++ if (snprintf(template, sizeof(template), "%s/runc.XXXXXX", prefix) < 0) ++ return -1; ++ ++ /* ++ * Now try memfd, it's much nicer than actually creating a file in STATEDIR ++ * since it's easily detected thanks to sealing and also doesn't require ++ * assumptions about STATEDIR. ++ */ ++ *fdtype = EFD_MEMFD; ++ fd = memfd_create(RUNC_MEMFD_COMMENT, MFD_CLOEXEC | MFD_ALLOW_SEALING); ++ if (fd >= 0) ++ return fd; ++ if (errno != ENOSYS && errno != EINVAL) ++ goto error; ++ ++#ifdef O_TMPFILE ++ /* ++ * Try O_TMPFILE to avoid races where someone might snatch our file. Note ++ * that O_EXCL isn't actually a security measure here (since you can just ++ * fd re-open it and clear O_EXCL). ++ */ ++ *fdtype = EFD_FILE; ++ fd = open(prefix, O_TMPFILE | O_EXCL | O_RDWR | O_CLOEXEC, 0700); ++ if (fd >= 0) { ++ struct stat statbuf = {}; ++ bool working_otmpfile = false; ++ ++ /* ++ * open(2) ignores unknown O_* flags -- yeah, I was surprised when I ++ * found this out too. As a result we can't check for EINVAL. However, ++ * if we get nlink != 0 (or EISDIR) then we know that this kernel ++ * doesn't support O_TMPFILE. ++ */ ++ if (fstat(fd, &statbuf) >= 0) ++ working_otmpfile = (statbuf.st_nlink == 0); ++ ++ if (working_otmpfile) ++ return fd; ++ ++ /* Pretend that we got EISDIR since O_TMPFILE failed. */ ++ close(fd); ++ errno = EISDIR; ++ } ++ if (errno != EISDIR) ++ goto error; ++#endif /* defined(O_TMPFILE) */ ++ ++ /* ++ * Our final option is to create a temporary file the old-school way, and ++ * then unlink it so that nothing else sees it by accident. ++ */ ++ *fdtype = EFD_FILE; ++ fd = mkostemp(template, O_CLOEXEC); ++ if (fd >= 0) { ++ if (unlink(template) >= 0) ++ return fd; ++ close(fd); ++ } ++ ++error: ++ *fdtype = EFD_NONE; ++ return -1; ++} ++ ++static int seal_execfd(int *fd, int fdtype) ++{ ++ switch (fdtype) { ++ case EFD_MEMFD: ++ return fcntl(*fd, F_ADD_SEALS, RUNC_MEMFD_SEALS); ++ case EFD_FILE: { ++ /* Need to re-open our pseudo-memfd as an O_PATH to avoid execve(2) giving -ETXTBSY. */ ++ int newfd; ++ char fdpath[PATH_MAX] = {0}; ++ ++ if (fchmod(*fd, 0100) < 0) ++ return -1; ++ ++ if (snprintf(fdpath, sizeof(fdpath), "/proc/self/fd/%d", *fd) < 0) ++ return -1; ++ ++ newfd = open(fdpath, O_PATH | O_CLOEXEC); ++ if (newfd < 0) ++ return -1; ++ ++ close(*fd); ++ *fd = newfd; ++ return 0; ++ } ++ default: ++ break; ++ } ++ return -1; ++} ++ ++static int try_bindfd(void) ++{ ++ int fd, ret = -1; ++ char template[PATH_MAX] = {0}; ++ char *prefix = secure_getenv("_LIBCONTAINER_STATEDIR"); ++ ++ if (!prefix || *prefix != '/') ++ prefix = "/tmp"; ++ if (snprintf(template, sizeof(template), "%s/runc.XXXXXX", prefix) < 0) ++ return ret; ++ ++ /* ++ * We need somewhere to mount it, mounting anything over /proc/self is a ++ * BAD idea on the host -- even if we do it temporarily. ++ */ ++ fd = mkstemp(template); ++ if (fd < 0) ++ return ret; ++ close(fd); ++ ++ /* ++ * For obvious reasons this won't work in rootless mode because we haven't ++ * created a userns+mntns -- but getting that to work will be a bit ++ * complicated and it's only worth doing if someone actually needs it. ++ */ ++ ret = -EPERM; ++ if (mount("/proc/self/exe", template, "", MS_BIND, "") < 0) ++ goto out; ++ if (mount("", template, "", MS_REMOUNT | MS_BIND | MS_RDONLY, "") < 0) ++ goto out_umount; ++ ++ ++ /* Get read-only handle that we're sure can't be made read-write. */ ++ ret = open(template, O_PATH | O_CLOEXEC); ++ ++out_umount: ++ /* ++ * Make sure the MNT_DETACH works, otherwise we could get remounted ++ * read-write and that would be quite bad (the fd would be made read-write ++ * too, invalidating the protection). ++ */ ++ if (umount2(template, MNT_DETACH) < 0) { ++ if (ret >= 0) ++ close(ret); ++ ret = -ENOTRECOVERABLE; ++ } ++ ++out: ++ /* ++ * We don't care about unlink errors, the worst that happens is that ++ * there's an empty file left around in STATEDIR. ++ */ ++ unlink(template); ++ return ret; ++} ++ ++static ssize_t fd_to_fd(int outfd, int infd) ++{ ++ ssize_t total = 0; ++ char buffer[4096]; ++ ++ for (;;) { ++ ssize_t nread, nwritten = 0; ++ ++ nread = read(infd, buffer, sizeof(buffer)); ++ if (nread < 0) ++ return -1; ++ if (!nread) ++ break; ++ ++ do { ++ ssize_t n = write(outfd, buffer + nwritten, nread - nwritten); ++ if (n < 0) ++ return -1; ++ nwritten += n; ++ } while(nwritten < nread); ++ ++ total += nwritten; ++ } ++ ++ return total; ++} ++ ++static int clone_binary(void) ++{ ++ int binfd, execfd; ++ struct stat statbuf = {}; ++ size_t sent = 0; ++ int fdtype = EFD_NONE; ++ ++ /* ++ * Before we resort to copying, let's try creating an ro-binfd in one shot ++ * by getting a handle for a read-only bind-mount of the execfd. ++ */ ++ execfd = try_bindfd(); ++ if (execfd >= 0) ++ return execfd; ++ ++ /* ++ * Dammit, that didn't work -- time to copy the binary to a safe place we ++ * can seal the contents. ++ */ ++ execfd = make_execfd(&fdtype); ++ if (execfd < 0 || fdtype == EFD_NONE) ++ return -ENOTRECOVERABLE; ++ ++ binfd = open("/proc/self/exe", O_RDONLY | O_CLOEXEC); ++ if (binfd < 0) ++ goto error; ++ ++ if (fstat(binfd, &statbuf) < 0) ++ goto error_binfd; ++ ++ while (sent < statbuf.st_size) { ++ int n = sendfile(execfd, binfd, NULL, statbuf.st_size - sent); ++ if (n < 0) { ++ /* sendfile can fail so we fallback to a dumb user-space copy. */ ++ n = fd_to_fd(execfd, binfd); ++ if (n < 0) ++ goto error_binfd; ++ } ++ sent += n; ++ } ++ close(binfd); ++ if (sent != statbuf.st_size) ++ goto error; ++ ++ if (seal_execfd(&execfd, fdtype) < 0) ++ goto error; ++ ++ return execfd; ++ ++error_binfd: ++ close(binfd); ++error: ++ close(execfd); ++ return -EIO; ++} ++ ++/* Get cheap access to the environment. */ ++extern char **environ; ++ ++int ensure_cloned_binary(void) ++{ ++ int execfd; ++ char **argv = NULL; ++ ++ /* Check that we're not self-cloned, and if we are then bail. */ ++ int cloned = is_self_cloned(); ++ if (cloned > 0 || cloned == -ENOTRECOVERABLE) ++ return cloned; ++ ++ if (fetchve(&argv) < 0) ++ return -EINVAL; ++ ++ execfd = clone_binary(); ++ if (execfd < 0) ++ return -EIO; ++ ++ if (putenv(CLONED_BINARY_ENV "=1")) ++ goto error; ++ ++ fexecve(execfd, argv, environ); ++error: ++ close(execfd); ++ return -ENOEXEC; ++} +diff --git a/libcontainer/nsenter/nsexec.c b/libcontainer/nsenter/nsexec.c +index 3c74c63..a6ec725 100644 +--- a/libcontainer/nsenter/nsexec.c ++++ b/libcontainer/nsenter/nsexec.c +@@ -353,6 +353,9 @@ static struct nsenter_config process_nl_attributes(int pipenum, char *data, int + return config; + } + ++/* Defined in cloned_binary.c. */ ++extern int ensure_cloned_binary(void); ++ + void nsexec(void) + { + int pipenum; +@@ -364,6 +367,11 @@ void nsexec(void) + return; + } + ++ if (ensure_cloned_binary() < 0) { ++ pr_perror("could not ensure we are a cloned binary"); ++ exit(1); ++ } ++ + /* make the process non-dumpable */ + if (prctl(PR_SET_DUMPABLE, 0, 0, 0, 0) != 0) { + pr_perror("Failed to set process as non-dumpable"); diff -Nru runc-0.1.1+dfsg1/debian/patches/series runc-0.1.1+dfsg1/debian/patches/series --- runc-0.1.1+dfsg1/debian/patches/series 2017-02-01 12:48:05.000000000 +0800 +++ runc-0.1.1+dfsg1/debian/patches/series 2019-03-19 00:50:07.000000000 +0800 @@ -1,2 +1,3 @@ disable-failing-tests.patch cve-2016-9962.patch +CVE-2019-5736.patch
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